Synthesis and characterization of Fe-doped TiO2 hollow spheres for dye-sensitized solar cell applications

Fe-doped TiO2 hollow spheres (THs@Fe) with various Fe contents, 0, 0.25, 0.50, 0.75 and 1.00 mol%, were prepared using carbon templates and further employed as photoanode for dye-sensitized solar cells. The analytical results indicated that the hollow structure of THs@Fe promoted an effective light penetration and scattering capability, which resulted in increased light-harvesting efficiency. The increase in specific surface area and pore volume caused enhancement of dye molecules adsorbed on the photoanodes, which directly affected the performance of the DSSCs. The highest power conversion efficiency, 6.025 +/- 0.141%, was obtained from 18NR/THs@0.25Fe bilayer photoelectrodes with a JSC of 15.392 +/- 0.458 mA cm(-2), V-OC of 0.759 +/- 0.001 V, and FF of 0.516 +/- 0.018. The highest achieved PCE value was attributed to formation of oxygen vacancies and other defect states generating the shallow electron traps that are essential for charge transport, electron lifetime and resulted in the DSSCs performance.